Device for holding a photoreceptor sheet

ABSTRACT

A device for holding a photoreceptor sheet onto a drum of an electro-photography printing device comprises first and second holding surfaces that are configured to hold an edge of the photoreceptor sheet from opposite directions by pressing against the sheet in a substantially perpendicular direction with respect to the surface of the sheet, wherein at least the second holding surface is pre-loaded.

BACKGROUND

Electro-photography printing devices including photoreceptors forcreating a latent image that may be subsequently developed and printedare known in the art. Typically, the photoreceptor is made up of a thinphotoreceptor sheet attached to a rotatable drum. Typically, thephotoreceptor sheet is periodically replaced due to damage. Duringoperation, a charger uniformly charges the photoreceptor. The drum isrotated and a laser writer discharges the photoreceptor in selectedareas to create a latent image. Continued rotation of the drum bringsthe selectively charged photoreceptor into contact engagement with adeveloper roller for developing the latent image. The developed latentimage is then transferred to a desired substrate. Alternatively, theremay be provided an intermediate transfer member, which may be a drum orbelt and which is in operative engagement with the photoreceptor bearingthe developed image

One system is described in U.S. Pat. No. 5,508,790 to Belinkov et al.entitled “Photoreceptor Sheet and Imaging System Utilizing Same” whichis incorporated herein by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter regarded is particularly and distinctly claimed inthe concluding portion of the specification. Non-limiting examples ofembodiments of the present invention are described below with referenceto figures attached hereto, which are listed following this paragraph.In the figures, identical structures, elements or parts that appear inmore than one figure are generally labeled with a same symbol in all thefigures in which they appear. Dimensions of components and featuresshown in the figures are chosen for convenience and clarity ofpresentation and are not necessarily shown to scale. For example, thedimensions of some of the elements may be exaggerated relative to otherelements for clarity.

FIG. 1 is a holding device according to some embodiments of the presentinvention;

FIG. 2 is a longitude sectional view of a holding device according tosome embodiments of the present invention.

FIG. 3A is a cross-sectional view of a holding device according to someembodiments of the present invention;

FIG. 3B is a schematic illustration of an electrical grounding path of ametallic layer of the photoreceptor sheet through the holding deviceaccording to some embodiments of the present invention;

FIG. 4 is a schematic illustration of a photoreceptor mounted on a drumwith a holding device according to some embodiments of the presentinvention;

FIG. 5 is a schematic illustration of a handle for removably mounting aphotoreceptor sheet onto a drum according to some embodiments of thepresent invention;

FIGS. 6A and 6B are schematic illustrations of a handle on the holdingdevice for removably mounting a photoreceptor sheet onto a drumaccording to some embodiments of the present invention.

It will be appreciated that for simplicity and clarity of illustration,elements shown in the figures have not necessarily been drawn to scale.Further, where considered appropriate, reference numerals may berepeated among the figures to indicate corresponding or analogouselements.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

In the following description, exemplary, non-limiting embodiments of theinvention incorporating various aspects of the present invention aredescribed. For purposes of explanation, specific configurations anddetails are set forth in order to provide a thorough understanding ofthe embodiments. However, it will also be apparent to one skilled in theart that the present invention may be practiced without the specificdetails presented herein. Furthermore, well-known features may beomitted or simplified in order not to obscure the present invention.Features shown in one embodiment may be combined with features shown inother embodiments. Such features are not repeated for clarity ofpresentation. Furthermore, some unessential features are described insome embodiments.

In the design of a faster printer, the present inventors have found thatthe lifespan of the photoreceptor sheet has been further limited. It hasbeen found that faster printing increases the stresses on thephotoreceptor and periodically leads to disengagement of thephotoreceptor from the drum and/or mechanical damage to the thinphotoreceptor sheet. This reduces its lifetime.

An aspect of some embodiments of the invention is the provision of animproved device for holding a thin photoreceptor sheet onto a drum of anelectro-photography printing device.

According to some embodiments of the present invention, the improveddevice includes a holding surface engaging the sheet by moving towardthe sheet in a substantially perpendicular direction to the surface ofthe sheet. Force is transmitted to the sheet over a surface area engagedwith the holding surface facilitating substantially uniform holdingpressure over that area. The holding surface is an improvement overexisting devices that engage the sheet by rotating an element that issubstantially tapered and/or a leaf spring that engages the sheet over aline. The tapered end of the rotating element presses the sheet againsta wall, transmitting force to the sheet over a line and/or over aminimal area. Providing a holding surface that engages the sheet in asubstantially perpendicular direction as is provided in embodiments ofthe present invention, increases the holding robustness of the deviceand reduces stresses imposed on the sheet that can lead to damage of thesheet.

According to some embodiments of the present invention, the holdingsurface is an end surface of a clamping element that slides along achannel. In some exemplary embodiments, the clamping element rests on arotatable shaft that is operative to translate the clamping elementresponsive to a rotation of the shaft. In some exemplary embodiments,the shaft engages the clamping element on a surface opposite that of theholding surface.

According to some embodiments of the present invention, a secondclamping element engages the sheet from an opposite direction. In someexemplary embodiments, the second clamping element is preloaded by aspring. The preload spring can be positioned in a number of locationswith respect to the second clamping element. In some exemplaryembodiments, the spring is a wave spring having a length substantiallycorresponding to a length of the sheet. In some exemplary embodiments,the preload force of the spring is adjustable. In some exemplaryembodiments adjustment to the preload force is facilitated with a sliderand an associated set screw operative to press against the spring.

According to some embodiments of the present invention, the improveddevice includes a substantially rigid holding surface backed by apre-loaded spring. The holding surface engages the sheet by movingtoward the sheet in a substantially perpendicular direction to thesurface of the sheet and engages the sheet over a substantially flatsurface. As is described herein above, force is transmitted to the sheetover the surface area of the holding surface facilitating substantiallyuniform holding pressure over the surface area of the sheet engaged withthe holding surface.

An aspect of some embodiments of the present invention is the provisionof an improved device for removably holding a thin photoreceptor sheetonto a drum of an electro-photography printing device. According to someembodiments of the present invention the device includes a handle thatcan, by rotation, effect engagement and/or disengagement of thephotoreceptor sheet from the drum. In some exemplary embodiments, thehandle is fixed to the rotating shaft described above.

According to some embodiments of the present invention, the deviceincludes a mechanism handle for engagement and/or disengagement of thephotoreceptor sheet from the drum. In some exemplary embodiments, atleast one part of the mechanism handle is fixed to the shaft while otherparts are attached to drum. According to some embodiments of the presentinvention, the mechanism handle eases operation of the device forholding the thin photoreceptor sheet onto the drum, e.g. reduces theforce employed for operating the device.

An exemplary embodiment of the present invention provides a device forholding a photoreceptor sheet onto a drum of an electro-photographyprinting device comprising first and second holding surfaces that areconfigured to hold an edge of the photoreceptor sheet from oppositedirections by pressing against the sheet in a substantiallyperpendicular direction with respect to the surface of the sheet,wherein at least the second holding surface is pre-loaded.

In some embodiments, the first and the second holding surfaces aresurfaces of a corresponding first and second clamping element.

In some embodiments, at least the first clamping element rests on arotatable shaft.

In some embodiments, the first clamping element approaches and recedesfrom the second holding surface in response to rotation of the shaft.

In some embodiments, the shaft has a cross sectional shape that includesa circular portion and a flat portion.

In some embodiments, the first clamping element recedes from the secondclamping element in response to the first clamping element resting onthe flat portion of the shaft.

In some embodiments, at least one of the first or the second holdingsurface is pre-loaded by a spring.

In some embodiments, the spring is a wave spring.

In some embodiments, the length of the spring corresponds to at leastthe length of the edge of the photoreceptor sheet.

In some embodiments, the spring is a leaf spring.

In some embodiments, the spring rests on the second clamping element ona surface opposite the holding surface of the second clamping element.

In some embodiments, the device comprises a sliding element at leastpartially resting on the spring and a set screw configured to translatethe sliding element over the spring.

In some embodiments, the sliding element and the set screw areconfigured for adjusting the pre-load of the spring.

In some embodiments, the drum includes a slot on the perimeter of thedrum and wherein the device is positioned on the drum proximal to theslot so that the slot forms an entryway into the device.

In some embodiments, the device comprises a handle fixed to therotatable shaft, wherein the handle is operative to hold and release thephotoreceptor sheet from the drum.

In some embodiments, the photoreceptor sheet is a foil.

In some embodiments, the photoreceptor sheet has a thickness between0.07 and 0.11 mm.

In some embodiments, the device applies a holding force at least 250 Kgon the photoreceptor sheet.

In some embodiments, the device applies a holding pressure of at least70 MPa.

In some embodiments, the device is configured for removably fixing thephotoreceptor sheet onto the drum.

In some embodiments, the device is configured for providing anelectrical path between the photoreceptor sheet and the drum.

An exemplary embodiment of the present invention provides a device forholding a photoreceptor sheet onto a drum of an electro-photographyprinting device, the device comprising first and second holding surfacesthat are configured to clamp an edge of the photoreceptor sheet fromopposite directions by pressing against the sheet in a substantiallyperpendicular direction with respect to the surface of the sheet, and ahandle associated with the holding device, wherein the handle isoperative to hold and release the photoreceptor sheet from the drum.

In some embodiments, at least one of the first or the second holdingsurfaces is pre-loaded by a wave spring.

In some embodiments, the device applies a holding force at least 250 Kgon the photoreceptor sheet.

In some embodiments, the device is configured for providing anelectrical path between the photoreceptor sheet and the drum.

According to some embodiments of the present invention, a holdingmechanism is integrated onto a photoreceptor drum of anelectro-photography printing device and implemented to removably lock aphotoreceptor sheet onto the photoreceptor drum. Reference is now madeto FIGS. 1-3A showing a holding device 150 configured for locking aphotoreceptor sheet onto the photoreceptor drum, a longitude sectionalview of the holding device and a cross-sectional view of the holdingdevice according to some embodiments of the present invention. Accordingto some embodiments of the present invention, holding device and/orlocking mechanism 150 includes a shaft 210, a clamping element 110, e.g.a lower clamping element, a clamping element 120, e.g. an upper clampingelement, and a spring 250. According to some embodiments of the presentinvention, holding device 150 is configured to receive an edge of aphotoreceptor sheet 105 through a cavity 130 and to hold the edge of thesheet between clamping element 110 and clamping element 120 positionedat an end of cavity 130. In some exemplary embodiments, cavity 130 isformed by a volume between an extrusion 133 and an extrusion 136 of theholding device.

According to some embodiments of the present invention, holding device150 includes a slider 240 that is configured to adjust the pre-loadingforce in spring 250. In some exemplary embodiments, a set screw 310pushes slider 240 so as to push down on spring 250 and thereby increasethe pre-load force. Releasing the force on slider 240 with set screw 310reduces the pre-loading in spring 250. According to some embodiments ofthe present invention, a return spring 115 may be included to separateclamping element 110 and 120.

According to some embodiments of the present invention, while the holderis in open position, there is a gap between sliders 120 and 110, whichallow the photoreceptor sheet to enter between them. According to someembodiments of the present invention, during an open state, returnspring 115 may separate clamping element 110 and 120. In this position,the return spring separates the clamping elements so that thephotoreceptor sheet 105 may be inserted between the clamping elements.According to some embodiments of the present invention, during an openstate, set screw 310 is adjusted to push slider 240 so as to push downon spring 250 and thereby set the desired the pre-load force. In oneexemplary embodiment, set screw 310 is adjusted so that the tip and/ortapered portion of push slider 240 slides until touching a wall ofextrusion 133.

According to embodiments of the present invention, during the openposition, the photoreceptor sheet 105 may be inserted through volumeand/or cavity 130 between the clamping elements 110 and 120 and up untila wall of extrusion 133.

During initiation of a locking state of holding device 150, shaft 210 isrotated clockwise and, in response to the rotation, clamping element 110approaches clamping element 120 in a substantially perpendiculardirection with respect to the end surfaces of clamping element 110 andclamping element 120. As clamping element 110 approaches clampingelement 120, clamping element 110 presses against clamping element 120which is typically pre-loaded by a spring 250. During a locking state ofholding device 150, clamping element 110 and clamping element 120presses against the edge of the photoreceptor sheet which is insertedbetween them. According to some embodiments of the present invention,during initiation of a release state of holding device 150, shaft 120 isrotated counter clockwise again and in response to this rotation,clamping element 110 recedes from clamping element 120 in asubstantially perpendicular direction with respect to the end surfacesof clamping element 110 and clamping element 120 the gap between them iscreated and releases the hold on the photoreceptor sheet. Since theclamping elements do not traverse the surface of the photoreceptorsheet, the force that can be applied is not limited as it is in theprior art by stresses in the photoreceptor sheet caused by such sliding.

In some exemplary embodiments, clamping element 110 is configured torest on shaft 210 with a surface opposite to the surface engaging thephotoreceptor sheet. Typically, spring 250 is positioned over clampingelement 120 on a surface opposite the surface of clamping element 120that engages the photoreceptor sheet. In some embodiments of theinvention, rotatable shaft 210 has a substantially cylindrical circularcross section with a section sliced off, as shown in FIG. 3A. The slicedoff section forms a substantially flat surface 215. By rotating shaft210, the shaft moves from touching clamping element 110 on flat surface215 to touching clamping element 110 on its circular circumference. As aresult, clamping element 110 translates toward the photoreceptor sheetpositioned between clamping element 110 and clamping element 120 andpushes against clamping element 120. Optionally, the edge of the slicedoff section may be rounded to facilitate smooth movement of clampingelement 110 as shaft 210 is rotated. Optionally, the rotatable shaft hascylindrical oval cross section or an eccentric cross section thatfacilitates sliding clamping element 110 toward and away from clampingelement 120 in response to rotation of the shaft.

The present inventors have found that the clamping element structure ofholding device 150 facilitates higher and more uniform pressure on thesheet as compared to prior art devices.

In some exemplary embodiments, clamping element 120 is pre-loaded byspring 250. Pre-loading the clamping element with a spring increases thegrip on the photoreceptor sheet and improves the uniformity of the forcedistribution over the edge of the sheet that is engaged by the holdingdevice. In some exemplary embodiments of the present invention, spring250 is a wave spring that extends over the length of the holding device.In one exemplary embodiment, spring 250 may comprise a leaf spring thatextends over the length of holding device. In another exemplaryembodiment, spring 250 comprises a series of springs positioned over thelength of the holding device.

According to some embodiments of the present invention, the pre-loadadjustment mechanism including set screw 310 and slider 240 facilitatespre-loading the wave spring 250 after assembly of clamping elements 110and 120 and slider 240 inside the extrusion 133. In some exemplaryembodiments, the assembly of the elements of the holding device, e.g.clamping elements 110 and 120 and slider 240, absent of the pre-loadforce provides for easier assembly.

According to some embodiments of the present invention, holding device150 can apply a holding force of approximately 250 Kg and/or 70 MPa,although lesser or greater force can be used depending on the stress towhich the photoreceptor sheet is subjected during printing.

Typically clamping elements 110 and 120 are rigid elements with flatsurfaces. Optionally, clamping elements 110 and 120 may include ridgesand/or protrusions etched and/or in some way formed onto a surface ofthe clamping elements, e.g. a surface of the clamping elements engagingthe sheet, so that the ridges are forced into the sheet and hold it moresecurely. In some exemplary embodiments, clamping elements 110 and 120may be coated, e.g. coated with a material to improve hold on thephotoreceptor sheet, for example by increasing friction with the sheet.

According to some embodiments of the present invention, shaft 210 and asurface of the slider 110 resting on the shaft are coated with amaterial to minimize friction during rotation of shaft. In someexemplary embodiments, shaft 210 and the bottom surface of clampingelement 110 are coated with chrome and/or nickel.

Reference is now made to FIG. 3B showing an electrical grounding path ofa metallic layer of the photoreceptor sheet through the holding deviceto the drum according to some embodiments of the present invention.Typically, the photoreceptor sheet includes three layers, layer 106,107, and 108 of which the middle layer 107 of the sheet is a metal layerand layers 106 and layer 108 are non-metallic. According to someembodiments of the present invention, upon engagement of the sheet withholding device 150, the sheet is in electrical contact with the drumthrough the holding device. According to some embodiments of the presentinvention, the metal layer of the sheet is exposed on the leading edgeof the sheet, e.g. the edge of sheet 105 that is held by holding device150 and when engaged in the holding device establishes electricalcontact with clamping element 110. Typically, clamping element 110 isfabricated from an electrically conducting material, e.g. a metallicmaterial without any non-conductive coatings. According to someembodiments of the present invention, a grounding path 151 isestablished from the exposed edge of sheet 105, through clamping element110, shaft 210, extrusion 133, flange 167, to the drum. Shaft 210,extrusion 133, and flange 167 are fabricated from electricallyconducting material and are in electrical contact with each other.

Reference is now made to FIG. 4 showing a schematic illustration of aphotoreceptor sheet mounted on a drum and locked into place with aholding device according to the embodiment of the present inventiondescribed above with respect to FIGS. 1-3. According to some embodimentsof the present invention, holding device 150 is integrated into a drum100. Holding device 150 is positioned on drum 100 proximal to a slot 155on the perimeter of the drum. Holding device 150 is positioned on drum100 so that slot 155 forms an entryway into cavity 130 of holding device150.

To mount photoreceptor sheet 105 onto the drum, one end of the sheet isinserted into slot 155 and thus into cavity 130 so that sheet 105 ispositioned between clamping element 110 and clamping element 120 at theend of cavity 130.

According to some embodiments of the present invention, the outersurface of drum 100 as well as extrusions 133 and 136 are shaped nearslot 155 to provide a slope so that the insertion of the photoreceptorsheet is facilitated. Further, in some exemplary embodiments, the otherend of the photoreceptor sheet extends long enough to overlay slot 155so as to avoid liquid toner entering cavity 130. According to someembodiments of the present invention, the photoreceptor sheet is a foil,e.g. a thin foil. In some exemplary embodiments, the sheet thicknessranges between 0.07 and 0.11 mm, e.g. 0.078-0.079 mm, approximately 0.08mm, approximately 0.09 mm and/or 0.093 mm.

According to some embodiments of the present invention, the holdingdevice provides improved ability to clean residual material from thephotoreceptor sheet that may get stuck inside the holding device. Forexample, the holding device can be easily assembled and disassembledfrom the drum by two or more screws 169 on flange 167 for cleaning. Insome exemplary embodiments, once the holding device is disassembled anair pressure gun pointed to cavity 130 may be used to remove residualsthat may get stuck inside the holding device. In some exemplaryembodiments, the holding device may be disassembled and cleansed, e.g.the sliders, wave spring and shaft may be disassembled for cleaning.Typically, cleaning of the holding device may be performed on site, e.g.the cleaning may take approximately 10 minutes to an hour during whichthe printer cannot print. This is an improvement over previously knownholding devices where the disassembly of the holding device is moredifficult and cleansing of the holding device is typically performed inthe lab and not on site. During this time, the printer cannot be used.

Reference is now made to FIGS. 5 and 6 showing schematic illustrationsof a handle for removably mounting a photoreceptor sheet onto a drumaccording to some embodiments of the present invention. According tosome embodiments of the present invention, handle 410 is rigidlyconnected to shaft 210. Rotating shaft 210 with handle 410 in acounter-clockwise direction orients flat surface 215 of shaft 210 sothat it faces and/or touches clamping element 110. Clamping element 110rests on shaft 210 and therefore recedes from clamping element 120 andphotoreceptor 105 and rests on the flat surface 215 currently facingclamping element 110. In the open position, photoreceptor 105 may beinserted and/or removed from the holding device, e.g. for replacement.Rotating shaft 210 with handle 410 in a clockwise direction providesorienting a substantially circular surface of shaft 210 so that it facesand touches clamping element 110. Clamping element 110 is configured torest on shaft 210 and therefore is pushed toward clamping element 120and photoreceptor 105. The radius of the circular portion of the crosssection of shaft 210 is larger than the radius of the flat portion ofthe cross section. The change in radius between the circular and flatportions initiates sliding of clamping element 110 toward and away fromclamping element 120 and the photoreceptor sheet between them.

In the closed position, photoreceptor 105 is clamped and fixed onto drum100. One or more stoppers may be provided to limit the rotation ofhandle 410 between the open and closed state of the handle. A mechanismto lock the handle in a closed position may be included. The position ofhandle 410 as shown in FIG. 5 is optionally a closed position of thehandle. The closed position on the handle is such that the handle willnot obstruct operation of the printer, e.g. while the drum is rotating.In some exemplary embodiments of the present invention, the handle mayhave a length between 5-20 cm, e.g. 6 cm or 12 cm. The force on thehandle to operate opening and closing may range between 10-150 Ndepending on the length of the handle and the force on the pre-loadsprings. For example, for a spring force of approximately 1300 N, aforce approximately between 10-70N on the handle may be employed for ahandle having a length of 6 cm. For larger spring forces, e.g. 4000 N, alonger handle may be used, e.g. 12 cm with a force on the handle ofapproximately 10-80 N.

Reference is now made to FIGS. 6A and 6B showing schematic illustrationsof a handle on a holding device for removably mounting a photoreceptorsheet onto a drum according to some embodiments of the presentinvention. In FIG. 6A the handle is in a closed position and in FIG. 6Bthe handle is in an open position. According to some embodiments of thepresent invention, a gear transmission may be used to reduce the forceapplied to the handle for operation. One or more gears, e.g. gears 520,530, and 535 may be used for this purpose. According to some exemplaryembodiments of the present invention, lifting handle 503 serves torotate shaft 210 in a clockwise direction so that flat surface 215 ofshaft 210 is oriented to face clamping element 110. Lowering lever 503serves to rotate shaft 210 in a counter-clockwise direction so that thecircular portion of the cross section of shaft 210 is oriented to faceclamping element 110. In one exemplary embodiment, the number of teethin gear 535 is 80, the number of teeth in gear 530 is 16 and the numberof gear teeth in gear 520 is 24, facilitating a gear reduction of 80/24.According to an exemplary embodiment, the addition of lever 510 mayfacilitate a reduction of approximately 8 giving a combined forcereduction of 11.33. Typically, handle 503 is shorter than handle 410used in the handle mechanism shown in FIG. 5, for example the handle maybe half the length so that the overall force reduction as compared to asimpler handle mechanism shown in FIG. 5 may be approximately 5-6. Othergear ratios and handle mechanisms may be implemented to achieve variousforce reductions.

It should be further understood that the individual features describedhereinabove can be combined in all possible combinations andsub-combinations to produce exemplary embodiments of the invention.Furthermore, not all elements described for each embodiment areessential. In many cases such elements are described so as to describe abest more for carrying out the invention or to form a logical bridgebetween the essential elements. The examples given above are exemplaryin nature and are not intended to limit the scope of the invention whichis defined solely by the following claims.

The terms “include”, “comprise” and “have” and their conjugates as usedherein mean “including but not necessarily limited to”.

The invention claimed is:
 1. A device for holding a photoreceptor sheetonto a drum of an electro-photography printing device comprising: firstand second clamping elements comprising first and second holdingsurfaces, respectively, to hold an edge of the photoreceptor sheet fromopposite directions by pressing against the sheet in a substantiallyperpendicular direction with respect to the surface of the sheet, inwhich at least the second clamping element is pre-loaded with a firstspring biasing the second holding surface toward the first holdingsurface; and in which the first and second holding surfaces are engagedwith the photoreceptor sheet via a rotatable shaft mechanically coupledto the first clamping mechanism, the rotatable shaft, when rotated,moving the first clamping mechanism relative to the second clampingmechanism, in which the shaft comprises a cross sectional shapecomprising a circular portion and a flat portion.
 2. The deviceaccording to claim 1, wherein the first clamping element engages withand disengages from the second holding surface in response to rotationof the shaft.
 3. The device according to claim 2 wherein the firstclamping element recedes from the second clamping element in response tothe first clamping element resting on the flat portion of the shaft. 4.The device according to claim 1 wherein the first holding surface ispre-loaded by a second spring, the second spring being biased toseparate the first and second holding surfaces.
 5. The device accordingto claim 1 wherein the first spring is a wave spring.
 6. The deviceaccording to claim 5 wherein the length of the first spring correspondsto at least the length of the edge of the photoreceptor sheet.
 7. Thedevice according to claim 1 wherein the first spring is a leaf spring.8. The device according to claim 1 wherein the first spring rests on thesecond clamping element on a surface opposite the holding surface of thesecond clamping element.
 9. The device according to claim 1 comprising:a sliding element at least partially resting on the first spring; and aset screw configured to translate the sliding element over the firstspring.
 10. The device according to claim 9 wherein the sliding elementand the set screw are configured for adjusting the pre-load of the firstspring.
 11. The device according to claim 1 wherein the drum includes aslot on the perimeter of the drum and wherein the device is positionedon the drum proximal to the slot so that the slot forms an entryway intothe device.
 12. The device according to claim 1, further comprising ahandle fixed to the rotatable shaft, wherein the handle is operative torotate the shaft to engage and disengage the photoreceptor sheet fromthe drum.
 13. The device according to claim 1 wherein the photoreceptorsheet is a foil.
 14. The device according to claim 1 wherein thephotoreceptor sheet has a thickness between 0.07 and 0.11 mm.
 15. Thedevice according to claim 1 wherein the device applies a holdingpressure of at least 70 MPa.
 16. The device according to claim 1 whereinthe device is configured for removably fixing the photoreceptor sheetonto the drum.
 17. The device according to claim 1 wherein the devicecreates an electrical ground between the photoreceptor sheet and thedrum.
 18. A device for holding a photoreceptor sheet onto a drum of anelectro-photography printing device comprising: first and secondclamping elements comprising first and second holding surfaces,respectively, to hold an edge of the photoreceptor sheet from oppositedirections by pressing against the sheet in a substantiallyperpendicular direction with respect to the surface of the sheet; and ahandle associated with the holding device, wherein the handle isoperative to hold and release the photoreceptor sheet from the drum, inwhich the second clamping element comprises: a first spring biasing thesecond holding surface toward the first holding surface; a slidingelement resting on the first spring; and a set screw to translate thesliding element over the first spring, in which the sliding element andset screw adjust the pre-load the first spring.
 19. The device accordingto claim 18 in which the first spring is a wave spring.
 20. The deviceaccording to claim 18 wherein the device applies a holding pressure ofat least 70 MPa on the photoreceptor sheet.
 21. The device according toclaim 18 wherein the device is configured for providing an electricalpath between the photoreceptor sheet and the drum.
 22. A device forholding a photoreceptor sheet onto a drum of an electro-photographyprinting device comprising: first and second clamping elementscomprising first and second holding surfaces, respectively, to hold anedge of the photoreceptor sheet from opposite directions by pressingagainst the sheet in a substantially perpendicular direction withrespect to the surface of the sheet, in which the second clampingelement comprises: a first spring biasing the second holding surfacetoward the first holding surface; a sliding element mechanically coupledto the first spring; and a set screw to translate the sliding elementover the first spring, in which the sliding element and set screw adjustthe pre-load the first spring.